U.S. patent application number 14/183295 was filed with the patent office on 2014-10-02 for optical module, optical communication equipment, and optical transmission device.
This patent application is currently assigned to Hitachi Metals, Ltd.. The applicant listed for this patent is Hitachi Metals, Ltd.. Invention is credited to Kouki Hirano, Takumi Kobayashi, Hiroki Yasuda.
Application Number | 20140294340 14/183295 |
Document ID | / |
Family ID | 51597829 |
Filed Date | 2014-10-02 |
United States Patent
Application |
20140294340 |
Kind Code |
A1 |
Yasuda; Hiroki ; et
al. |
October 2, 2014 |
OPTICAL MODULE, OPTICAL COMMUNICATION EQUIPMENT, AND OPTICAL
TRANSMISSION DEVICE
Abstract
An optical module includes a circuit board, an optical element
on the circuit board, a semiconductor circuit element thereon and
electrically coupled with the optical element, an optical
connection member formed on a back surface of the circuit board and
including an optical fiber receiving groove, and a pressing plate
disposed on a side opposite to the circuit board of the optical
connection member so as to fix the optical fiber. The semiconductor
circuit element is mounted nearer a tip side of the circuit board
in relation to the optical element such that the circuit board, the
optical connection member and a tip part of the optical fiber are
sandwiched between the semiconductor circuit element and the
pressing plate. The circuit board includes a plurality of
electrodes to be electrically coupled with an equipment side
circuit board formed on a tip part of a back surface of the circuit
board.
Inventors: |
Yasuda; Hiroki; (Milto,
JP) ; Hirano; Kouki; (Hitachinaka, JP) ;
Kobayashi; Takumi; (Hitachi, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Hitachi Metals, Ltd. |
Tokyo |
|
JP |
|
|
Assignee: |
Hitachi Metals, Ltd.
Tokyo
JP
|
Family ID: |
51597829 |
Appl. No.: |
14/183295 |
Filed: |
February 18, 2014 |
Current U.S.
Class: |
385/14 |
Current CPC
Class: |
G02B 6/4257 20130101;
G02B 6/428 20130101; G02B 6/4214 20130101; G02B 6/423 20130101;
G02B 6/4267 20130101 |
Class at
Publication: |
385/14 |
International
Class: |
G02B 6/12 20060101
G02B006/12 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2013 |
JP |
2013-064046 |
Claims
1. An optical module, comprising: a circuit board; an optical
element mounted on a surface of the circuit board; a semiconductor
circuit element mounted on a surface of the circuit board and
electrically coupled with the optical element; an optical
connection member formed on a back surface of the circuit board and
comprising an optical fiber receiving groove for enclosing a tip
part of an optical fiber inserted through an end side of the
circuit board and optically coupling the optical fiber received in
the optical fiber receiving groove with the optical element; and a
pressing plate disposed on a side opposite to the circuit board of
the optical connection member so as to fix the optical fiber while
enclosing the optical fiber in the optical fiber receiving groove,
wherein the semiconductor circuit element is mounted nearer a tip
side of the circuit board in relation to the optical element such
that the circuit board, the optical connection member and a tip
part of the optical fiber are sandwiched between the semiconductor
circuit element and the pressing plate, and wherein the circuit
board comprises a plurality of electrodes to be electrically
coupled with an equipment side circuit board formed on a tip part
of a back surface of the circuit board.
2. The optical module according to claim 1, wherein a difference in
coefficient of thermal expansion between the semiconductor circuit
element and the pressing plate is not more than 20 ppm.
3. The optical module according to claim 1, wherein the pressing
plate is disposed so as to extend at least from a position facing
the semiconductor circuit element to a position facing the optical
element.
4. The optical module according to claim 1, wherein the pressing
plate is disposed such that a tip surface thereof contacts the
equipment side circuit board in electrically coupling the
electrodes with the equipment side circuit board.
5. The optical module according to claim 1, wherein the circuit
board further comprises an electrode for inspection used for
inspecting the optical element or the semiconductor circuit element
formed on a surface thereof.
6. The optical module according to claim 1, wherein the circuit
board is formed into a rectangle of not more than 3 mm on a side,
and wherein a length of the electrode is not more than 0.5 mm.
7. An optical communication equipment, comprising the optical
module and the equipment side circuit board according to claim 1,
wherein the electrodes of the optical module are connected to the
equipment side circuit board.
8. The optical communication equipment according to claim 7,
wherein the electrodes formed on the back surface of the circuit
board are electrically connected to an equipment side electrode
formed on a surface of the equipment side circuit board, and
wherein a potting comprising a resin is disposed so as to
collectively cover the optical element and the semiconductor
circuit element mounted on the surface of the circuit board of the
optical module and an equipment side element mounted on a surface
of the equipment side circuit board.
9. An optical transmission device, comprising the optical modules
according to claim 1 at both end parts of the optical fiber.
Description
[0001] The present application is based on Japanese patent
application No. 2013-064046 filed on Mar. 26, 2013, the entire
contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an optical module, an optical
communication equipment using the optical module, and an optical
transmission device using the optical module.
[0004] 2. Description of the Related Art
[0005] An optical module is known which converts an electrical
signal input from an equipment etc. to an optical signal and
outputs it to an optical fiber, or which converts the optical
signal input from the optical fiber to the electrical signal and
outputs it to the equipment etc.
[0006] As an example of the optical module, an optical module is
known which comprises a lens block having a lens or a mirror, an
optical fiber, and an optical element, and the lens block set
facing a light emitting part or a light receiving part of the
optical element, and the optical fiber is optically coupled with
the optical element via the lens block.
[0007] Prior art documents related to the invention of this
application may include JP-A-2011-095295.
SUMMARY OF THE INVENTION
[0008] In recent years an optical module has been used in various
uses and, depending on the uses, it may be strongly desired to
downsize an optical module. For examples, even by a subminiature
camera etc. for commercial use, it is not possible to secure a
sufficient storage space for the optical module. Thus, a
subminiature optical module downsized to size of around several
millimeters may be desired.
[0009] But it is difficult to realize such a subminiature optical
module as described above because there is a limit to downsize the
optical module comprising the lens block.
[0010] It is an object of this invention to provide an optical
module that can realize further downsizing, as well as an optical
communication equipment and an optical transmission device using
the optical module.
(1) According to one embodiment of the invention, an optical module
comprises:
[0011] a circuit board;
[0012] an optical element mounted on a surface of the circuit
board;
[0013] a semiconductor circuit element mounted on a surface of the
circuit board and electrically coupled with the optical
element;
[0014] an optical connection member formed on a back surface of the
circuit board and comprising an optical fiber receiving groove for
enclosing a tip part of an optical fiber inserted through an end
side of the circuit board and optically coupling the optical fiber
received in the optical fiber receiving groove with the optical
element; and
[0015] a pressing plate disposed on a side opposite to the circuit
board of the optical connection member so as to fix the optical
fiber while enclosing the optical fiber in the optical fiber
receiving groove,
[0016] wherein the semiconductor circuit element is mounted nearer
a tip side of the circuit board in relation to the optical element
such that the circuit board, the optical connection member and a
tip part of the optical fiber are sandwiched between the
semiconductor circuit element and the pressing plate, and
wherein the circuit board comprises a plurality of electrodes to be
electrically coupled with an equipment side circuit board formed on
a tip part of a back surface of the circuit board.
[0017] In the above embodiment (1) of the invention, the following
modifications and changes can be made.
[0018] (i) A difference in coefficient of thermal expansion between
the semiconductor circuit element and the pressing plate is not
more than 20 ppm.
[0019] (ii) The pressing plate is disposed so as to extend at least
from a position facing the semiconductor circuit element to a
position facing the optical element.
[0020] (iii) The pressing plate is disposed such that a tip surface
thereof contacts the equipment side circuit board in electrically
coupling the electrodes with the equipment side circuit board.
[0021] (iv) The circuit board further comprises an electrode for
inspection used for inspecting the optical element or the
semiconductor circuit element formed on a surface thereof.
[0022] (v) The circuit board is formed into a rectangle of not more
than 3 mm on a side, and wherein a length of the electrode is not
more than 0.5 mm.
(2) According to another embodiment of the invention, an optical
communication equipment comprises the optical module and the
equipment side circuit board according to the above embodiment (1),
wherein the electrodes of the optical module are connected to the
equipment side circuit board.
[0023] In the above embodiment (2) of the invention, the following
modifications and changes can be made.
[0024] (vi) The electrodes formed on the back surface of the
circuit board are electrically connected to an equipment side
electrode formed on a surface of the equipment side circuit board,
and wherein a potting comprising a resin is disposed so as to
collectively cover the optical element and the semiconductor
circuit element mounted on the surface of the circuit board of the
optical module and an equipment side element mounted on a surface
of the equipment side circuit board.
(3) According to another embodiment of the invention, an optical
transmission device comprises the optical modules according to the
above embodiment (1) at both end parts of the optical fiber.
EFFECTS OF THE INVENTION
[0025] According to one embodiment of the invention, an optical
module can be provided that can realize further downsizing, as well
as an optical communication equipment and an optical transmission
device using the optical module.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The preferred embodiments according to the invention will be
explained below referring to the drawings, wherein:
[0027] FIGS. 1A-1C are the view schematically showing an optical
module according to the embodiment of the invention, and FIG. 1A
and FIG. 1B are perspective views schematically showing optical
modules, and FIG. 1C is a side view schematically showing the state
that said optical module is coupled with an equipment side circuit
board;
[0028] FIG. 2 is a plane view schematically showing an optical
module in FIGS. 1A-1C.
[0029] FIG. 3A and FIG. 3B are perspective views schematically
showing a circuit board and an optical waveguide used for an
optical module in FIGS. 1A-1C;
[0030] FIG. 4 is a perspective views schematically showing an
optical fiber holding member used in an optical module in FIGS.
1A-1C;
[0031] FIG. 5 is a side view schematically showing an optical
module according to a modification of the invention; and
[0032] FIG. 6 is a side view schematically showing the state that
an optical module according to a modification of the invention is
coupled with an equipment side circuit board.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] The embodiment of the invention will be explained below
according to the drawings attached.
[0034] FIGS. 1A-1C are the view schematically showing an optical
module according to the embodiment of the invention, and FIG. 1A
and FIG. 1B are perspective views schematically showing said
optical modules, and FIG. 1C is a side view schematically showing
the state that said optical module is coupled with an equipment
side circuit board. In addition, FIG. 2 is a plane view
schematically showing said optical module.
[0035] As shown in FIGS. 1A-1C and FIG. 2, the optical module 1
comprises a circuit board 2, an optical element 3 mounted on a
surface S of the circuit board 2, a semiconductor circuit element 4
mounted on the surface S of the circuit board 2 and electrically
coupled with the optical element 3, an optical connection member 14
formed on a back surface R of the circuit board 2 and having an
optical fiber receiving groove 6 (as shown in FIG. 3) to receive
(or enclose) a tip end of an optical fiber 5 imported from the end
side of the circuit board 2 and optically coupling the optical
fiber 5 received in the groove 6 with the optical element 3, and a
pressure plate 8 set on the opposite side of the circuit board 2 of
an optical waveguide 7 and fixing it in the state that the optical
fiber 5 is received in the groove 6.
[0036] As is shown in FIG. 3, a double sided wiring flexible
printed circuit (FPC), on both surfaces of which wiring patterns 2a
are formed, is used as the circuit board 2. The wiring pattern 2a
formed on the surface S and the wiring pattern 2a formed on the
back surface R are electrically coupled each other via a through
hole 2b. In the embodiment of this invention, the circuit board 2
is formed into a rectangle of 3 mm or less on a side, more
specifically, not less than 1 mm and not more than 3 mm on a
side.
[0037] The optical element 3 composed of a surface light emitting
element, for example, VCSEL (Vertical Cavity Surface Emitting
Laser) etc. or a surface light receiving element, for example, PD
(Photo Diode) etc. and the semiconductor circuit board element 4
are mounted on the surface S of the circuit board 2 by flip chip
mounting method. As the semiconductor circuit board element 4, in
case that the optical element 3 is the light emitting element, a
driver IC which drives the light emitting element is used, and in
case that the optical element 3 is the light receiving element,
then the amplifier IC which amplifies an electrical signal from the
light receiving element is used.
[0038] In the embodiment of the invention, the optical connection
member 14 is formed on the back surface R of the circuit board 2,
and is composed of the optical waveguide 7 having the optical fiber
receiving groove 6 (as shown in FIG. 3) which encloses a tip part
of the optical fiber 5 inserted from the end side of the circuit
board 2 and optically coupling the optical fiber 5 enclosed in the
optical fiber receiving groove 6 with the optical element 3.
[0039] The optical waveguide 7 is formed on the back surface R of
the circuit board 2. A through hole 11 which passes a light input
or output by the optical element 3 is formed at the position facing
a light emitting part or a light receiving part of the optical
element 3 in the circuit board 2. In addition, the through hole 11
is optional in case that the circuit board 2 is made of a material
which has a transparency to the light of a wavelength used.
[0040] The optical waveguide 7 (not shown) is comprised of a core
extending parallel to the circuit board 2 along the extension
direction of an optical fiber 5 and a clad covering around the
core, and is arranged so that a core of an optical fiber 5 and the
core of the optical waveguide 7 are optically coupled each other
when inserting the optical fiber 5 into the optical fiber receiving
groove 6. A V-groove is formed at the position facing a light
emitting part or a light receiving part of the optical element 3 in
the optical waveguide 7, and the groove has a mirror 7a which
inclines 45 degrees for an optical axis of the core of the optical
waveguide 7 and reflects a light by using the difference of
refractive index between the core of the optical waveguide land the
air. By converting the optical axis 90 degrees by the mirror 7a, a
light emitting part or a light receiving part of the optical
element 3 and the core of the optical waveguide 7 are optically
coupled each other. The optical waveguide 7 is formed to extend
from the end part of the circuit board 2 to the position facing the
optical element 3.
[0041] In the optical module 1, an adhesive is filled around the
optical fiber 5, and the optical fiber 5 is fixed to the optical
fiber receiving groove 6 by curing the adhesive in the state that
the optical fiber 5 is pressed by the pressing plate 8. In
particular, the processes in assembling the optical module 1 can be
simplified by using ultraviolet curing type resin as a stuff of the
adhesive and by using a stuff which has a transparency to
ultraviolet rays as a stuff of the pressing plate 8 because the
adhesive can be cured by irradiating ultraviolet rays in the state
that the optical fiber 5 is pressed by the pressing plate 8.
[0042] An optical fiber holding member 10 is set at the end part of
a circuit board 2 which strongly fixes an optical fiber 5 and
controls the damage of an extension part of an optical fiber 5. The
optical fiber holding member 10 is formed by processing a metal
plate of aluminum, and stainless, etc.
[0043] As shown in FIG. 4, the optical fiber holding member 10 is
composed of an optical fiber holding part 10a, a cross section of
which is formed into a U character form so as to cover both sides
and an undersurface (the side of the pressing plate 8) of the
optical fiber 5, and a fixing part 10b lengthening from an
undersurface (the side of the pressing plate 8) of the optical
fiber holding part 10a toward a tip of the circuit board 2 and
fixed on the opposite surface of the side of the optical waveguide
7 of the pressing plate 8 by the adhesive. The adhesive which has
low hardness after cured (a soft adhesive which permits the
movement of the optical fiber 5 to some extent after cured) is
filled with inside of the optical fiber holding part 10a and is
cured, to reduce the damages in the optical fiber 5 because of the
concentration of the stress at the extension part of the optical
fiber 5 from the optical waveguide 7. The fixing part 10b is formed
into like a T character form by expanding the width of the tip part
of it, so that the optical fiber holding part 10a is strongly fixed
on the surface of the pressing plate 8 by increasing the contact
area between the fixing part 10b and the pressing plate 8.
[0044] In the optical module 1 according to the embodiment of the
invention, the semiconductor circuit element 4 is mounted on the
circuit board 2, the position which the semiconductor circuit
element 4 is mounted on is nearer to the tip side of the circuit
board 2 (the tip side from which the optical fiber 5 is inserted)
than the position which the optical element 3 is mounted on, and
the optical module 1 is arranged such that the circuit board 2, the
optical waveguide 7, and the tip part of the optical fiber 5 are
sandwiched between the semiconductor circuit element 4 and the
pressing plate 8, and plural electrodes 12 electrically coupled
with an equipment side circuit board 21, which is a target for
coupling with the optical module 1, are formed on the tip part of
the back surface R of the circuit board 2 in a row.
[0045] In the embodiment of the invention, six electrodes 12 are
provided in a row at equal intervals along the width direction of
the circuit board 2, but the number of electrodes 12, the size of
intervals etc. are not limited in this case. However, if the length
of the electrodes 12 is too large, the entire circuit board 2 will
be longer so as to increase the size. The length of the electrodes
12 is desirably as short as possible, and preferably not more than
0.5 mm. In the embodiment, the length of the electrodes 12 is set
to be about 0.2 mm and the disposition pitch of the electrodes 12
in the width direction is set to be about 0.16 mm. The total
thickness of the optical module 1 is about 0.8 mm in which the
semiconductor circuit element 4, the optical element 3, the circuit
board 2, the optical waveguide 7, the pressing plate 8 and the
optical fiber fixing member 10 are formed sequentially.
[0046] In the optical module 1 according to the embodiment of the
invention, the optical module 1 is arranged such that the circuit
board 2, the optical waveguide 7, and the tip part of the optical
fiber 5 are sandwiched between the semiconductor circuit element 4
and the pressing plate 8, so if the difference in coefficient of
thermal expansion between the semiconductor circuit element 4 and
the pressing plate 8 is large, then there is a possibility of
occurring such a trouble, for example, that a curve occurs in the
whole optical module 1 and a solder of the optical element 3 or the
semiconductor circuit element 4 comes off. Therefore, it is
preferable that the coefficients of thermal expansion of the
semiconductor circuit element 4 and the pressing plate 8 are set as
close as possible, in particular, it is preferable that the
difference in coefficient of thermal expansion between the
semiconductor circuit element 4 and the pressing plate 8 is not
more than 20 ppm. Specifically, as a material of the pressing plate
8, it is preferable to use a glass, for example, a quartz glass the
coefficient of thermal expansion of which is close to that of the
semiconductor circuit element 4 and has a transparency to
ultraviolet rays.
[0047] In addition, in the embodiment of the invention, the
electrodes 12 are formed on the tip part of the back surface of the
circuit board 2 which is opposite to the surface on which the
semiconductor circuit element 4 is mounted, so if pushing a probe
for inspection to the electrodes 12 when inspecting the optical
element 3 or the semiconductor circuit element 4, such a trouble,
for example, that the solder of the optical element 3 or the
semiconductor circuit element 4 comes off may occur because the
optical element 3 or the semiconductor circuit element 4 is
hard-pushed to the work top. Therefore, in the embodiment of the
invention, an electrode 13 for inspection used for inspecting the
optical element 3 or the semiconductor circuit element 4 is formed
on the surface S of the circuit board 2 and the inspection is done
by pushing a probe for inspection to the electrode 13 for
inspection when inspecting. In addition, in the embodiment of the
invention, the wiring pattern 2a formed around the optical element
3 and on the tip side of the surface S of the circuit board 2 is
formed in large size so as to be easy to push a probe.
[0048] An optical transmission device according to the embodiment
of the invention is obtained by providing at one end part of the
optical fiber 5 the optical module 1 using a light emitting element
as the optical element 3 and providing at the other end part of the
optical fiber 5 the optical module 1 using a light receiving
element as the optical element 3.
[0049] In addition, as shown in FIG. 1C, an optical communication
equipment 100 according to the embodiment of the invention is
obtained by electrically coupling the electrodes 12 of the optical
module 1 with the equipment side circuit board 21.
[0050] The optical communication equipment 100 is used for a
subminiature camera of the industrial use etc. The equipment side
circuit board 21 is a circuit board for controlling the optical
communication equipment 100 etc. and an equipment side electrode 22
for coupling the electrodes 12 of the optical module 1 is formed at
the tip part of the surface thereof An equipment side element 23
including a semiconductor circuit element which controls the
optical communication equipment 100 etc. is mounted on the surface
of the equipment side circuit board 21.
[0051] The optical communication equipment 100 is constructed by
electrically coupling the electrodes 12 formed on the back surface
R of the optical module 1 with the equipment side electrode 22
formed on the surface of the equipment side circuit board 21 by a
solder etc.
[0052] In the embodiment of the invention, a potting 24 of a resin
is set so as to cover the optical element 3 and the semiconductor
circuit element 4, mounted on the surface S of the circuit board 2
of the optical module 1, and the equipment side element 23 mounted
on the surface of the equipment side circuit board 21 together for
the purpose of increasing the reliability of the optical module 1
under the high-temperature and high-humidity environment. In case
of forming the electrodes 12 on the surface S of the circuit board
2, for example, it isn't possible to set the potting 24 so as to
cover the optical element 3 and the semiconductor circuit element
4, and the equipment side element 23 together and hence the potting
24 is needed to be set on both surfaces of the circuit board 2. But
in case of forming the electrodes 12 on the back surface R of the
circuit board 2, as is formed in the optical module 1, it is
possible to locate the optical element 3 and the semiconductor
circuit element 4, and the equipment side element 23 on the surface
side of the equipment side circuit board 21 together and to set the
potting 24 so as to cover these elements together.
[0053] Effects of the embodiment of the invention are explained
below.
[0054] In the optical module 1 according to the embodiment of the
invention, the semiconductor circuit element 4 is mounted on the
circuit board 2, the position which the semiconductor circuit
element 4 is mounted on is nearer to the tip side of the circuit
board 2 (on the tip side through which the optical fiber 5 is
inserted) than the position which the optical element 3 is mounted
on, and the optical module 1 is arranged such that the circuit
board 2, the optical waveguide 7, and the tip part of the optical
fiber 5 are sandwiched between the semiconductor circuit element 4
and the pressing plate 8, and the plural electrodes 12 electrically
coupled with the equipment side circuit board 21, which is a target
for coupling with the optical module 1, are aligned on the tip part
of the back surface R of the circuit board 2.
[0055] In the conventional optical module, the semiconductor
circuit element 4 is usually formed as close as possible to the
electrodes 12 and is usually formed on the tip side of the optical
element 3 (on the side of the electrodes 12) to suppress the
deterioration of high-speed electrical signal.
[0056] On the other hand, in the optical module 1 according to the
embodiment of the invention, it is possible to cut the wasteful
space on the circuit board 2 and plan further downsizing of the
optical module 1 by mounting the semiconductor circuit element 4 on
the tip side of the circuit board 2 of the optical element 3. In
addition, in the optical module 1, the length of one side of the
circuit board 2 is not more than 3 mm, and such the optical module
1 is extremely smaller than the conventional optical module, so it
is possible to reduce the distance between the electrodes 12 and
the circuit board 2 and to suppress the deterioration of high-speed
electrical signal even when the semiconductor circuit element 4 is
mounted on the tip side of the circuit board 2 of the optical
element 3.
[0057] By the way, a solder etc. is used in coupling the electrodes
12 with the equipment side circuit board 21. But if the optical
element 3 exists extremely near to the electrodes 12, a trouble may
be occur to the optical element 3 under the influence of heat to be
generated at the time of coupling work, such as soldering, etc. In
the optical module 1, since the optical element 3 is arranged on
the position of the circuit board 2 that is nearer to the tip side
(on the side of the electrodes 12) of the circuit board 2 than the
semiconductor circuit element 4, the influence of heat to be
generated at the time of coupling work to the optical element 3
increases.
[0058] Therefore, in the embodiment of the invention, the
electrodes 12 are formed on the back surface R of the circuit board
2 which is opposite to the surface on which the optical element 3
is mounted. By this way, it is possible to suppress the
deterioration of the optical element 3 caused by heat even if the
electrodes 12 are arranged near the optical element 3 in comparison
with the case that the electrodes 12 are formed on the surface on
which the optical element 3 is mounted, and is possible to plan
further downsizing of the optical module 1.
[0059] In addition, since the optical module 1 has such a structure
that the electrodes 12 are formed on the tip side of the circuit
board 2, the optical module 1 can be easy mounted on the equipment
side circuit board 21 by soldering etc. Besides, in the optical
module 1, the disposition pitch between the electrodes 12 is
extremely narrow (e.g. about 0.16 mm) and the length of the
electrodes 12 are extremely short (e.g. 0.2 mm), so it is difficult
to couple with a connector such as an FPC connector.
[0060] The invention is not always limited to the above embodiment,
and of course may be carried out by being appropriately modified
without departing from the scope thereof.
[0061] For example, in the embodiment of this invention, the
pressing plate 8 is placed only at the position facing to the
semiconductor circuit board 4, but the position of the pressing
plate 8 is not limited to this. For example, in an optical module
51 as shown in FIG. 5, it is possible to place the pressing plate 8
extending from the position facing to the semiconductor circuit
board 4 (as shown in FIG. 1C) to the position facing to the optical
element 3 by enlarging the pressing plate 8 toward the tip side
thereof. By placing the pressing plate 8 in this way, it is
possible to improve the mechanical strength of the optical module
51.
[0062] Furthermore, in an optical module 61 as shown in FIG. 6, it
may be possible to further extend the pressing plate 8 toward the
tip side thereof and place the pressing plate 8 so that the tip
surface of the pressing plate 8 contacts the equipment side circuit
board 21 in electrically coupling the electrodes 12 with the
equipment side circuit board 21. By placing the pressing plate 8 in
this way, it is possible to perform easily the alignment of the
optical module 61 and the equipment side circuit board 21. In this
case, it can be said that the pressing plate 8 plays all roles of
fixing the optical fiber 5, improving the mechanical strength of
the optical module 51, and positioning of the optical module
61.
* * * * *